The present application relates to encryption of formatted pages. More specifically, this relates to encryption of a page to be transmitted over a channel, e.g., a network such as the Internet.
Encryption includes the study of trying to increase the security of a system. Attacks on encryption attempt to defeat that security. A sufficiently complicated cryptosystem will make it effectively impossible to decode plaintext from only ciphertext. If sufficiently difficult, only a brute force method, i.e., a test of each of the possible keys, could recover the plaintext.
However, very complicated cryptosystems are often used for carrying out the encryption and decryption. For example, many of these complicated crypto systems use various techniques including multiple arithmetic operations, and attempts to smooth the frequency distribution of the resulting ciphertext.
The frequency distribution of the ciphertext can be used as a way to attempt to recover the plaintext. Many early cipher systems, in fact, were defeated using the principle of frequency analysis.
The trend in the art has been to make a more complicated cryptosystem based on more complicated mathematics. This in turn, however, requires higher processing requirements, and higher data handling capabilities. Many of these systems require a large portion of the message to be received before the entire decryption is carried out. Encryption on a thin client such as a handheld computer; personal digital assistant (“PDA”); or portable telephone can require a significant portion of the resources.